More practically, as Datacent notes, "If your hard drive makes noises like these and you are still able to access your files - backup immediately."
Hard drive sounds (Thanks, Fipi Lele!)
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.